Drop in the ocean

Early last month, to the delight of its UK developers, a deep-diving robot submarine designed to survey the hardest-to-reach regions of the ocean began to report its findings.

Autosub 6000, so-called because it can operate down to a depth of 6,000m, is the UK’s deepest-diving autonomous undersea vehicle (AUV). It is the brainchild of engineers from the Underwater Systems Laboratory (USL) at Southampton’s National Oceanography Centre(NOC) and is the latest stage in a programme that has been running for over 12 years.

The vehicle began life as Autosub, which was first trialled in Southampton’s Empress dock in 1996. Improvements in autonomy and range led to Autosub 3, which was able to operate at a depth of 1,600m. As well as being used to measure current and temperature in the Gulf Stream, this has carried out an under-ice mission measuring ice thickness and populations of krill in the Antarctic.

Autosub 6000, claimed to be suited to exploring 95 per cent of the world’s oceans, takes these capabilities a step further. On its current research mission it is fitted with a multi-beam bathymetric sonar to map the sea floor as part of an expedition under Dr Russell Wynn investigating potential threats from tsunamis, landslides and earthquakes on the western coasts of Europe.

‘We provide the AUV as a platform for scientists to run their experiments on,’ said project manager Dr Stephen McPhail, speaking from onboard the research vessel RSS James Cook. ‘It does the mission as designed, whether that is ploughing up and down through a water column to measure the properties of the water, or flying close to the seabed to map it.’

The fact that Autosub 6000 is in use so soon after its successful initial trials in September 2007 is a demonstration of the project’s success. It is supporting the scientists investigating historically large mud-flow events on the sea floor, mapping the areas in great detail and guiding coring operations from the ship.

‘The original plan was to do more engineering trials this year but when the opportunity for this cruise came along, it sounded ideal for us,’ said McPhail. ‘Right from the first mission, everything worked perfectly, we got very good image data back from its first dive when it surveyed the sea floor.’